Many (most? all?) allocators are guaranteed to give you back aligned pointers. For instance, jemalloc(3) on amd64 platforms will give back 16-byte aligned poin

Many (most? all?) allocators are guaranteed to give you back aligned pointers. For instance, jemalloc(3) on amd64 platforms will give back 16-byte aligned pointers: [...] The allocated space is suitably aligned (after possible pointer coercion) for storage of any type of object.